Pneumatic tire.



l. Ff. GAMMETER.

`PNEUMATIC TIRE.

M PucMloN FILED JULY 30.1915.

/NI/ENTo/e ATTO/wry incense.

'cierran lerares ramener JOHN R. GAMMETEE, F AKRON, OHC), ASSIGNOB, T0 THE B. F. GOOI-)RICH COMPAI'Y, 0F NEW YORK, N. vY., A CORPORATION OF NEW YORK.

PNEUIVIATIC TRE.

To all whom t may concern:

Be it known that l, JOHN R. (initiieren, a citizen of the United States, residing at ,Akron, in the county of Summit and State of Ohio, have invented certain new and useful Improvements in Pneumatic Tires, of

" "which the following is a specification.

1" This invention relates to pneumatic tires of flattened or oblate section adapted to present an increased area of tread surface in contact with the ground in comparison with the usual type having a substantially circu- 'lar section, thereby decreasingthe amount 'bf airpressure necessary to be carried in the 'tire in order to sustain a given load, and the "amount 'of destructive strain and bending to Avvhiclithewalls of the carcass are subjected, increasing the durability of the rubber tread and diminishing its tendency to separate `from the carcass.

ln constructing such a tire, it is necessary l" to include in connection with the tread wall `a series of flexible elements such as bands,

cords, wires or fabric layers `which are substantially inextensible in a circumferential direction, and a considerable problem is invvolved in so constructing these ineXtensible elements and combiningn them with the other elements of the tire as to provide a uniiied structure of maximum iieXibility which` will notrapidly disintegrate in service. ln my `atent No. 1,188,062 of June 20, 1916, .l

`have described a tire of this class having incorporated in its tread section a number of layers of rubberized cord each consisting of a length of cord wrapped in parallel turns circuxni''erentially about the tire, thev said cord layers being structurally incorporated in the carcass ot the tire casing by beinginterposed between, and vulcanized to, the

`plies of bias fabric which also constitute the .side `walls of the carcass and extend into the beads.; and in said patent, l havey broadly `claimed the invention common to it and the Specification of Letters Patent.

Patented Apr. i, i919.

v .application led July 30, 1915. Serial No. 42,742.

band separate or separable from the main tire carcass, so that in case of damage by cutting, the carcass can be repaired in the ordinary manner or replaced, and the inextensible 'element can be separately repaired or replaced at a relatively small cost.

Furthermore, by constructing the main tire casing or its carcass so that, even when deflated, it has the oblate forni which it assumes in service, preferably by making it on a core of oblate section the fabric elements of the carcass are set in the vulcanized rubber in the form necessary to properly distribute the working strains and pressures between the carcass and the inextensible element and allow the tire walls to bend in service withv the least amount of internal friction and working of the cord and fabric elements in opposition to each other and to the rubber with which. they are combined.

These tires are fespecially adapted for trucks and other heavy automobiles, and my present inventions, as disclosed in this and my aforesaid prior application, represent, so far as l am aware, the first instance of the successful production of a flat-section lieavy-duty pneumatic tire.

Of the accompanying,r drawings,

Figure l 'represents a perspective sectional view of a tire constructed in accordance with my invention, with parts of the inextensible band broken away.

Fig. 2 represents a sectional view of the tire casing and the mold iii which it is vulcanized.

In the drawings, l0 represents a tire casingwliose carcass is madeupgof a number of plies or layers ll of the usual frictioned woven` fabric laid on the bias, but the carcass may be of any desired construction,

`tlieterm fabric being used in a broad sense in the claims unless qualified as woven fabric. l2 is the breaker strip in the tread wall, and 13 is tbe outer wearing layer of rubber'vulcanized on the carcass. rflic marlginal portions or beads lil are shown 'as turned inwardly and forming inwardlyopen grooves i5 in which are located endless wire rings or cables 16 for securing the tire on the wheel rim, but any suitable bead construction may be employed.

rlllie casing is preferably built in oblatc form on a core l? of suitable shape, and "inclosed in an outer vulcanizing mold 18 of .similar shape, as represented in Fig. 2, so

that the fabric elements are disposed and set in the vulcanized rubber in approximately the form which they assume when in service, and which better adapts the tire to such service than if the carcass were vul*L canized in circular form. Al may, as shown, also allow a small clearance between the tire and mold-at the tread and sides, and provide lthe core 17 with suitable means for supplying and distributing fluid under pressure into the interior of the tire during vulcanization so as to distend and stretch it, avoid ,inflated or expanded condition.

The inextensible element is an endless band 22 of which a portion is shown in Fig. l, the same being composed of alternate layers of bias fabric 23 and flattened lrubberized cords 24, each cord layer consisting of a separate length wound circumferentially in a plurality of parallel convolutions or cord elements, the two ends and the intermediate turns of the outermost cord llayer being I shown in Fig. 1. The number of layers, both of cord and fabric, may be varied. The band is thickened in the middle where the cord layers are placed, and the fabric layers only are extended into the margins and preferably graduated in width, so that the band tapers to thin edges at the two sides. The fiattening of' the cord reduces the thickness of the band, but is obviously of less importance in a band of few layers than in one of many. Said band and the carcass, when combined as shown, will form a structure resisting the outward pressure of the air-tube in all directions, enabling the tire to retain its oblate form and presenting a smooth and regular surface for the` air-tube to bear against. Rubber for welding the cord and fabric layers ofthe band together ma be rovided in addition to the rubber with which they are impregnated or coated.

The band is built up ona suitable drum or mandrel, preferably collapsible2 wrapped with fabric and vulcanized `on said mandrel and is then removed and inserted in the carcass under the tread wall of the latter. It can be cemented in the carcass, butpref- Yerably is laid loosely therein so as to be removable in the saine' manner as an inner tube. The combination of incxtensible cord and bias-fabrillai'ei's T 'fha-ve `folind\well the use of a considerable number of layers in the band, in which case it is very diflicult to construct a band of suflicient strength without making one which is unduly stiff.v i 'l0 and subject to internal friction, heating and disintegration. My improved band is strong and at the same time flexible, and, in combination with a carcass vulcanized in oblate form, it is well adapted to give the advantages set forth in the introduction.

1. The combination of a substantially inresist the internal air pressure an along its inner circumference, a removable elastic inner air-tube adapted to bear outextensible pneumatic tire casing ada ted to V open wardly against the sides of said casing, and j a structurally-separate circumferentiallyinextensibile endless band confined against the innerV surface of the tread-wall ofthe casing by the pressure of the air tube against the sides of the latter, for maintaining the tire in an oblate cross-sectional form when inflated, the body of said band being substantially fiat transversely and comprising circumferentially-extending strain-resisting cord elements.

2. The combinationof a substantially 1neXtensible pneumatic tire casing adapted to resist the internal air pressure and cured in an oblate cross-sectional formv substantially the same as its iniated form,` said casing being open along its inner circumg ference, a removable elastic inner air-tube adapted to bear outwardly against the sides of the casing, and a structurally-separate'| inextensible transversely-fiat endless band comprising circumferentially-extending cord elements and confined against the inner surface of the tread-wall of the casing b 'the pressure of the air-tube against the si. es of" the latter, for maintaining the oblate form of the tire when iniiated.

. 3. The combination of a substantially in/ extensible pneumatic tire casing ada ted to resist the internal airressure an open along its inner circum erence, said Casin havin curve sides, a structurally-se arate, cir cumferentially-inextensible end ess fibrous a substantially-Hat tread wall an y' ica ical

band having a transversely-fiat relatively-v ,v thick body and relatively-na'roiiv tapered edges and positioned against t e inner sur. i

face of the tread-wall of the casing, and it removable elastic air-tube bearin l'outwardly the casin for transversely expanding the latter an holding its tread wall inwardlyv matic tire, said band having a transverselyflat, relatively-thick middle body cnflprisfz me.; -against-said band and against t e sides of meme? ing circumferentially-extending inextensible having a transversely-Mt. relativelytliiclr 1.0

cord elements7 and terminating in relativelymiddle body comprising rubberized circumnarrow tapered side edges so as to cover suberentially-extending cord elemente, and

stantially only the inner side of the treudrubberized Woven-fabric cover plies forming Wall of the tire and maintain the latter in relatively-narrow tapered margins. i

an oblate cross-sectional form. In testimony whereof l have hereunto set l5 5. An endless substantially-inextensible my hand this 29 day of July, 1915.

treadfband for insertion between the casing and air tube of a pneumatic tire, said band JOHN R. GAMMETER. 

